The Evening Standard traced PalTalk to an internet company based in New York, a mile from the World Trade Center site where Bin Laden’s al Qaeda network killed more than 3,000 people in the September 11 attacks.

The parent company, AVM Software, was founded in 1998 by lawyer Jason Katz. It is financed by Softbank Capital Partners (SCP), a venture capital firm headed by Masayoshi Son, a billionaire known as “Japan’s Bill Gates”.

SCP managing partner Mike Perlis is a director of AVM.

A PalTalk spokesman described the website as an “open service” which could not be routinely monitored because there were so many channels.

But after the Evening Standard told the company about the webcasts, executives in New York began emergency talks on whether to ban or restrict them.

No one at Softbank was available for comment.

Labour MP Andrew Dismore is today writing to both companies urging them to ban Bakri Mohammed from broadcasting on the site. He said: “At the very least this website has to be closed down or he has to be stopped from using it. I find it unbelievable that people like him are able to continue spreading their message of hatred with impunity.”

Scotland Yard and Britain’s security services are known to keep a close eye on the cleric.

Reports today suggest that detectives from the anti-terrorist squad have already begun an investigation into his activities on the internet.

PalTalk’s 25 million users worldwide can watch and listen to live broadcasts while typing their comments in discussion groups.

Bakri Mohammed, 46, addresses his followers for about 90 minutes every evening, speaking by mobile phone from central London. Last week he told his internet audience: “Al Qaeda and all its branches and organisations of the world, that is the victorious group andyou are obliged to join. There is no need … to mess about.”

Two nights later he claimed that dead holy warriors were calling on young British Muslims to fight, adding: “Where is your weapon? Come on to the jihad (holy war)”.

While stopping short of calling for terrorist attacks within Britain, he said Muslims should join the jihad “wherever you are”.

The Syrian-born cleric headed the al-Muhajiroun group, known for praising the 9/11 hijackers as the “magnificent 19” until he disbanded it last October.